2FLQ:
reference: Structure and Reactivity of a Thermostable Prokaryotic Nitric-oxide Synthase That Forms a Long-lived Oxy-Heme Complex., Sudhamsu J, Crane BR, J Biol Chem. 2006 Apr 7;281(14):9623-32. Epub 2006 Jan 11. PMID: 16407211

This OCA Structure page
uses Jmol, developed by the Jmol Development Team (documentation).